These studies are designed to evaluate the clinical benefits achieved by iron chelation in patients with chronic iron overload. Deferoxamine is administered by subcutaneous infusion and iron removal is determined by measurement of the serum ferritin and periodic non-invasive measurement of liver-iron concentration. Clinical status is evaluated by standard parameters including non-invasive testing of cardiac and endocrine function as indicated by the patient's age and risk category. The study is designed to document the natural history of severe beta thalassemia, treated effectively with regular transfusions and chelation therapy tailored to the patient's clinical status. The patients studied are both male and female, range in age from 5 to 70 years, and are Caucasian, African American, Oriental or Hispanic. Similar studies in adult patients with acquired bone marrow disorders requiring regular transfusions have also suggested a clinical benefit of Desferal treatment. Our current studies are focused on evaluating these patients in detail to determine the occurrence and rate of complications related to iron overload. These clinical studies employ a drug approved for the treatment of iron overload and are focused on determining it's efficacy. A study of 59 patients with homozygous beta thalassemia followed for periods ranging from 5-10 years has been completed. Patients who are highly compliant with deferoxamine have remained free of evidence of cardiac and endocrine disease, whereas the controlled population of poorly compliant patients has exhibited greater than 50% mortality. In the course of these studies we had the opportunity to compare the non- invasive measurement of liver iron with the standard ferritin. Although a correlation exists between the two parameters, we found that a single ferritin measurement in individuals patients is poorly predictive of the total iron burden.